This article presents an adaptation of the labour supply model applied to the independent medical sector. First, we model simultaneous General Practitioner (GP) decisions on both the leisure time and the consultation length for two payment schemes: fixed fees and unregulated fees. The objective of this econometric study is to validate the theoretical prediction that doctors under unregulated fees may make choices about the length of patient consultations independent of their personal leisure decision. Indeed, according to our empirical results, the bidirectional link between leisure choice and consultation length - verified with fixed fees - does not hold any longer under unregulated fees. Our findings can be seen as a necessary but not a sufficient condition to legitimize unregulated fees in general practice.